Photovoltaic systems in combination with covers over surfaces of water or photovoltaic systems immersed in water are known in the prior art.
Thus, U.S. Pat. No. 7,902,418 discloses a photovoltaic system which is integrated in water or adapted for use in a water environment and in which photovoltaic cells are attached to a sheet, known as a geomembrane. The geomembrane may in this case be arranged such that it is floating on the water or be suspended in the water, immersed to such an extent that the photovoltaic cells on the sheet are washed over by water, and consequently are cleaned and cooled. Various UV-resistant polymer coating materials as well as an inflatable geomembrane are disclosed.
United States patent application publication 2010/0294331 A1 discloses an arrangement of photovoltaic cells, embedded in a membrane or arranged on a membrane, which is placed as a cover over a water reservoir, that is, over the surface of a swimming pool or a pond, and which then serves for generating energy. The system as a whole floats on the water or else can be operated in an immersed state.
United States patent application publication 2011/0168235 discloses an arrangement of photovoltaic cells for generating electrical energy on a solid structure in sheet form (panel) immersed in water or floating on the water. The depth of immersion of the structure can be set as desired, from “floating” on the surface to “immersed” at a depth of for example two meters. The photovoltaic cells may be placed on flat or be formed in such a way that they are adjustable by means of linkages.
DE 198 57 174 A1 discloses a system of solar sheets floating in water, in which the sheet carrying the photovoltaic material is welded in between a lower bottom sheet and a transparent top sheet and in which intermediate spaces are provided between the sheets and can be filled on the one hand with air to regulate the depth of immersion and on the other hand with liquids, such as for instance alcohol, to achieve a lens effect.
DE 39 19 125 A1 discloses a low-density buoyant solar cell collector, the photovoltaic cells of which are embedded in a watertight manner in transparent plastic, with flushing holes arranged between the photovoltaic cells, intended for cleaning the surface or avoiding excessive water pressure in ocean swell.
DE 199 08 645 A1 discloses a floating solar collector with a thin-film photovoltaic material embedded in a watertight manner in a transparent sheet, the collector having loops or holes through which sticks of wood or bamboo that form the structure of the collector and provide the buoyancy can be pushed in.
The solutions known so far in the prior art of floating photovoltaic systems in the form of sheet laminates have the disadvantage that they cannot be walked on. Therefore, servicing and maintenance during operation are usually relatively difficult.